KR20090010718A - Power supply circuit of back light unit for liquid crystal display - Google Patents

Power supply circuit of back light unit for liquid crystal display Download PDF

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Publication number
KR20090010718A
KR20090010718A KR1020070074054A KR20070074054A KR20090010718A KR 20090010718 A KR20090010718 A KR 20090010718A KR 1020070074054 A KR1020070074054 A KR 1020070074054A KR 20070074054 A KR20070074054 A KR 20070074054A KR 20090010718 A KR20090010718 A KR 20090010718A
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South Korea
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backlight
power supply
transformer
liquid crystal
crystal display
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KR1020070074054A
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Korean (ko)
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윤창선
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엘지이노텍 주식회사
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Priority to KR1020070074054A priority Critical patent/KR20090010718A/en
Priority to US12/178,068 priority patent/US7859195B2/en
Publication of KR20090010718A publication Critical patent/KR20090010718A/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/24—Circuit arrangements in which the lamp is fed by high frequency ac, or with separate oscillator frequency
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Optics & Photonics (AREA)
  • Computer Hardware Design (AREA)
  • Theoretical Computer Science (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

A power supply circuit of a backlight unit for a liquid crystal display is provided to improve the differences of the brightness of the backlight unit due to the power source deviation. Each transformer transforms input power source. The power source outputted from each transformer is connected in each connector with the external backlight 1, and 2(L1)(L2). The electric trace 1, and 2(W1)(W2) include the other connector connected with each connector in the one-side end. The backlight and transformer are connected with each other. Each transformer and a connector are designed and placed on PCB. And PCB is installed in the one-side end of the liquid crystal display.

Description

액정표시장치의 백라이트유닛 전원공급회로 {POWER SUPPLY CIRCUIT OF BACK LIGHT UNIT FOR LIQUID CRYSTAL DISPLAY}Backlight unit power supply circuit for liquid crystal display device {POWER SUPPLY CIRCUIT OF BACK LIGHT UNIT FOR LIQUID CRYSTAL DISPLAY}

도 1은 ONE-BOARD 방식의 백라이트유닛 전원공급구조를 간략히 도시한 평면도.1 is a plan view briefly showing a power supply structure of the ONE-BOARD backlight unit.

도 2는 본 발명의 일실시예에 따른 구성을 간략히 도시한 블럭도.2 is a block diagram schematically showing a configuration according to an embodiment of the present invention.

도 3은 본 발명의 일실시예에 따른 구성을 보다 구체적으로 도시한 회로도.3 is a circuit diagram showing in more detail the configuration according to an embodiment of the present invention.

<도면의 주요부분에 대한 부호 설명><Description of Signs of Major Parts of Drawings>

10 : 전원공급회로 11 : 경로110: power supply circuit 11: path 1

12 : 경로2 13 : 전류편차보상부12: path 2 13: current deviation compensation unit

D : 액정표시장치 T1,T2 : 트랜스포머1,2D: liquid crystal display device T1, T2: transformer 1,2

CON1~CON4 : 커넥터1~4 W1,W2 : 전기배선1,2CON1 ~ CON4: Connector 1 ~ 4 W1, W2: Electric wiring 1,2

C1,C2 : 커패시터1,2 R1 :레지스터1C1, C2: Capacitor1,2 R1: Register1

본 발명은 액정표시장치의 백라이트유닛 전원공급회로에 관한 것이다. The present invention relates to a backlight unit power supply circuit of a liquid crystal display device.

일반적으로, 액정표시장치는 현재 디스플레이 장치를 필요로 하는 거의 모든 정보 처리 기기에 장착되어 사용된다. In general, liquid crystal display devices are currently used in almost all information processing equipment that requires a display device.

상기 액정표시장치는 액정의 특정한 분자배열에 전압을 인가하여 다른 분자배열로 변환시키고 이러한 분자 배열에 의해 발광하는 액정 셀(cell)의 복 굴절성, 선광성, 2색성 및 광 산란 특성 등의 광학적 성질의 변화를 시각 변화로 변환하는 것으로, 액정 셀에 의한 빛의 변조를 이용한 디스플레이 장치이다.The liquid crystal display device has an optical property such as birefringence, photoreactivity, dichroism, and light scattering characteristics of a liquid crystal cell that applies a voltage to a specific molecular array of liquid crystals, converts it into another molecular array, and emits light by the molecular array. It is a display device that uses the modulation of light by a liquid crystal cell by converting the change of the light into a visual change.

이러한, 액정표시장치는 자체적으로 발광하지 못하는 수광 소자이기 때문에, 액정 패널의 후면에 부착된 백라이트유닛(Back-light Unit)를 이용하여 액정패널을 조명한다. 액정 패널의 광 투과율은 인가된 전기적 신호에 따라 조절되며, 이에 대응되어 정지된 화상이나 움직이는 화상이 액정 패널 상에 표현된다. Since the liquid crystal display is a light receiving element that does not emit light by itself, the liquid crystal panel is illuminated by using a backlight unit attached to the rear side of the liquid crystal panel. The light transmittance of the liquid crystal panel is adjusted according to an applied electrical signal, and a still image or a moving image is correspondingly represented on the liquid crystal panel.

상기와 같이 액정패널로 광 공급을 수행하는 백라이트 유닛에서 사용되는 램프는 일반적으로 냉음극형광램프(Cold Cathode Fluorescent Lamp: CCFL)가 사용되고 있다.As a lamp used in the backlight unit for supplying light to the liquid crystal panel as described above, a cold cathode fluorescent lamp (CCFL) is generally used.

상기 냉음극형광램프는 우리에게 흔히 알려진 형광램프인 열음극 형광램프(Hot Cathode Fluorescent Lamp)와 거의 동일한 원리로 점등되지만, 열음극 형광램프가 열에 의한 전자방출로 점등되는 반면, 냉음극 형광램프는 전극에 가해지는 전계에 의한 전자방출로서 점등되며 발열량이 매우 적다는 차이를 보이고 있다.The cold cathode fluorescent lamp is lit on the same principle as the hot cathode fluorescent lamp (Hot Cathode Fluorescent Lamp), which is a fluorescent lamp commonly known to us. It turns on as the electron emission by the applied electric field, and shows a difference that the amount of heat generated is very small.

이러한 액정패널의 백라이트유닛은 인버터를 통해 공급되는 신호(전원)에 따라 동작하게 된다.The backlight unit of the liquid crystal panel operates according to a signal (power) supplied through an inverter.

최근 들어서는 액정표시장치가 대면적화 되면서 백라이트가 액정표시장치 양단에 설치되는데, 이러할 경우, 상기 인버터는 TWO-BOARD 방식(PCB가 Master, Slave 각 1장씩 있는 방식)으로 구현된다.In recent years, as a liquid crystal display device becomes large, a backlight is installed at both ends of the liquid crystal display device. In this case, the inverter is implemented in a TWO-BOARD method (a method in which one PCB is provided for each master and slave).

그러나, 액정표시장치(D)의 부피 축소 및 가격 경쟁력을 위해, 새로이 제안된 인버터는 첨부 도면 도 1에 도시된 바와 같이, ONE-BOARD 방식(Master, Slave 의 회로를 PCB(P) 1장에 구현한 방식) 이다.However, for the volume reduction and the price competitiveness of the liquid crystal display device (D), the newly proposed inverter is a circuit of the ONE-BOARD method (Master, Slave) to one PCB (P) as shown in the accompanying drawings. Implementation).

이러한 ONE-BOARD 방식 인버터에서의 문제점이 PCB(P)가 패널의 한쪽에 설치됨에 따라서(현재는 Master 쪽에 주로 설치됨) 다른 한쪽의 전류가 전기배선을 경유하여 타측의 백라이트(L2)까지 전달됨에 있어서, 전류가 패널로 누설되어 램프에 전달되는 전류가 줄어드는 문제가 있다.The problem with the ONE-BOARD type inverter is that as the PCB (P) is installed on one side of the panel (now installed mainly on the master side), the current on the other side is transmitted to the other backlight (L2) via the electrical wiring. In addition, there is a problem in that a current is leaked to the panel and the current delivered to the lamp is reduced.

이는 결과적으로, Master와 Slave의 전류에 편차가 발생되며, 램프의 전류 편차는 각 백라이트 간의 밝기를 상이하게 만든다. 이는, 곧 백라이트유닛의 휘도 편차로 이어져 액정표시장치의 출력 화면이 고르지 못한 문제점이 있다.As a result, a deviation occurs in the current between the master and the slave, and the current deviation of the lamp makes the brightness between the backlights different. This leads to a luminance deviation of the backlight unit, resulting in an uneven output screen of the liquid crystal display.

본 발명은 전원 편차에 의해 발생되는 백라이트유닛의 휘도 편차를 개선시킬 수 있다. The present invention can improve the luminance deviation of the backlight unit caused by the power deviation.

본 발명은 적어도 두개의 백라이트; 상기 백라이트로 각각 전원을 공급하는 전원 공급 경로들; 및 상기 적어도 두개의 전원 공급 경로들중, 경로의 길이가 타경로들보다 짧은 전원 공급 경로에 연결된 전류편차보상부를 포함한다. The present invention provides at least two backlights; Power supply paths respectively supplying power to the backlight; And a current deviation compensation unit of the at least two power supply paths connected to the power supply path whose length is shorter than that of other paths.

한편, 본 발명 중 상기 복수의 전원 공급 경로는 입력전원을 변압하는 트랜스포머; 상기 트랜스포머로부터 출력되는 전원을 외부의 백라이트와 접속시키는 커넥터; 상기 커넥터와 연결되는 다른 커넥터가 일측 단에 구비되어, 백라이트와 트랜스포머를 연결하는 전기배선을 포함하여 구성될 수 있다. On the other hand, the plurality of power supply path of the present invention includes a transformer for transforming the input power; A connector for connecting the power output from the transformer to an external backlight; Another connector connected to the connector may be provided at one end, and may include an electric wiring connecting the backlight and the transformer.

이때, 상기 트랜스포머와 커넥터는 PCB상에 설계 배치되며, 상기 PCB는 액정표시장치의 일측 단에 설치될 수 있다.In this case, the transformer and the connector are designed and arranged on the PCB, the PCB may be installed on one end of the liquid crystal display device.

또한, 상기 각 경로의 전기배선은 어느 하나는 다른 하나 보다 길게 마련될 수 있다. In addition, one of the electrical wiring of each path may be provided longer than the other.

또 한편, 본 발명 중 상기 전류편차보상부는 상기 각 경로 중 전기배선의 길이가 짧은 경로의 트랜스포머의 2차측과 커넥터사이에 접지와 병렬 연결되어 전원을 브랜칭(BRANCHING)하여 누설시키는 소자를 포함하여 구성될 수 있다.On the other hand, in the present invention, the current deviation compensation unit is configured to include a device that is connected to the ground in parallel with the ground between the connector and the secondary side of the transformer of the short path of the electrical wiring in each of the path to branching the power supply (leak) Can be.

이때, 상기 전류편차보상부는 트랜스포머의 2차측과 접지 사이에 직렬 연결되는 한 쌍의 커패시터와 상기 커패시터 중 접지 측 커패시터와 병렬 연결되는 레지스터를 포함하여 구성될 수 있다.In this case, the current deviation compensation unit may include a pair of capacitors connected in series between the secondary side and the ground of the transformer and a resistor connected in parallel with the ground side of the capacitor.

이하, 본 발명의 바람직한 실시 예에 대하여 첨부도면을 참조하여 상세히 설명하기로 한다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

도 2는 본 발명의 일실시예에 따른 구성을 간략히 도시한 블럭도이며, 도 3은 본 발명의 일실시예에 따른 구성을 보다 구체적으로 도시한 회로도이다.2 is a block diagram schematically showing a configuration according to an embodiment of the present invention, Figure 3 is a circuit diagram showing a configuration in more detail according to an embodiment of the present invention.

본 발명은 첨부 도면 도 2 및 도 3에 도시된 바와 같이, 화소 자체로는 발광하지 못하는 액정표시장치의 배후 양단 부분에 각각 설치되어 빛을 조사하는 백라이트(L1)(L2)를 위한 전원공급회로(10)에 있어서, 상기 양단의 백라이트(L1)(L2)로 각각 전원을 공급하는 전원공급회로(10)의 전원 공급 경로1, 2(11)(12) 중, 전기배선의 길이가 상대적으로 짧아 누설 전류가 적은 전원 공급 경로에 의도적 누설을 유도하는 전류편차보상부(13)를 포함하여서 된 것이다.2 and 3, the power supply circuit for the backlight (L1) (L2) for respectively irradiating light is installed on the rear end portions of the liquid crystal display device that does not emit light by the pixel itself In (10), the length of the electrical wiring is relatively long among the power supply paths 1 and 2 (11) and 12 of the power supply circuit 10 for supplying power to the backlights L1 and L2 at both ends. It includes a current deviation compensator 13 which induces intentional leakage in a power supply path having a short leakage current.

한편, 본 발명 중 상기 경로1, 2(11)(12)는 입력전원을 변압하는 각각의 트랜스포머1, 2(T1)(T2); 상기 각 트랜스포머1, 2(T1)(T2)로부터 출력되는 전원을 외부의 백라이트1, 2(L1)(L2)와 접속시키는 각각의 커넥터1, 2(CON1)(CON2); 상기 각 커넥터1, 2(CON1)(CON2)와 연결되는 다른 커넥터3, 4(CON3)(CON34)가 일측 단에 구비되어, 백라이트1, 2(L1)(L2)와 트랜스포머1, 2(T1)(T2)를 연결하는 전기배선1, 2(W1)(W2)를 포함하여 구성된다. Meanwhile, in the present invention, the paths 1 and 2 (11) and 12 are respectively transformers 1 and 2 (T1) (T2) for transforming an input power source; Connectors 1 and 2 (CON1) and CON2 for connecting the power output from the transformers 1 and 2 (T1) and T2 to the external backlights 1 and 2 (L1) and L2; Other connectors 3 and 4 (CON3) and CON34 connected to the respective connectors 1 and 2 (CON1) and CON2 are provided at one end thereof, and the backlights 1 and 2 (L1) and L2 and transformers 1 and 2 (T1). It comprises a electrical wiring 1, 2 (W1) (W2) connecting the (T2).

이와 같이 되면, 상기 스위칭부(MOS-FET)로부터 출력된 전원이 트랜스포머1, 2(T1)(T2)의 1차측에 인가되며, 이로 인해 트랜스포머1, 2(T1)(T2)는 각각 입력된 전원을 변압시켜 2차측으로 출력시킨다.In this case, the power output from the switching unit (MOS-FET) is applied to the primary sides of the transformers 1 and 2 (T1) and (T2), so that the transformers 1 and 2 (T1) and T2 are respectively input. The power is transformed and output to the secondary side.

그리되면, 출력된 전원은 각각 커넥터1, 2(CON1)(CON2)를 거쳐 커넥터3, 4(CON3)(CON4)를 통해 전기배선1, 2(W1)(W2)에 연결된 백라이트1, 2(L1)(L2)를 각각 점등시킨다. Then, the output power is connected to the electrical wiring 1, 2 (W1) (W2) via the connectors 1, 2 (CON1) (CON2) and the connectors 3, 4 (CON3) (CON4), respectively. Turn on L1) and L2 respectively.

이때, 상기 각 트랜스포머1, 2(T1)(T2)와 커넥터1, 2(CON1)(CON2)는 PCB상에 설계 배치되며, 상기 PCB는 액정표시장치의 일측 단에 설치된다.In this case, the transformers 1 and 2 (T1) and T2 and the connectors 1 and 2 (CON1) and CON2 are designed and arranged on a PCB, and the PCB is installed at one end of the liquid crystal display.

또한, 상기 경로1(11)과 경로2(12)의 각 전기배선1, 2(W1)(W2)는 어느 하나가 다른 하나 보다 길게 마련된다. 그리되는 이유는 상기 백라이트1, 2(L1)(L2)가 액정표시장치양단에 각각 설치되며, 상기 PCB는 각 백라이트1, 2(L1)(L2) 중 일측의 백라이트 부분에 설치되기 때문이다. In addition, each of the electric wirings 1 and 2 (W1) and W2 of the path 1 (11) and the path 2 (12) is provided longer than the other one. The reason for this is that the backlights 1 and 2 (L1) and L2 are respectively provided at both ends of the liquid crystal display, and the PCB is installed in the backlight portion of one of the backlights 1 and 2 (L1) and L2.

또 한편, 본 발명 중 상기 전류편차보상부(13)는 상기 경로1(11)과 경로2(12) 중 전기배선의 길이가 짧은 경로의 트랜스포머의 2차측과 커넥터 사이에 접지와 병렬 연결되어 전원을 브랜칭(BRANCHING)하여 누설시키는 소자를 포함한다.On the other hand, the current deviation compensation unit 13 of the present invention is connected in parallel with the ground between the connector and the secondary side of the transformer of the path of the shorter electric wiring of the path 1 (11) and the path 2 (12) power supply It includes a device for branching (BRANCHING) to leak.

이때, 전기배선의 길이는 일실시예적으로, 백라이트2(L2)를 연결하는 전기배선의 길이가 더 긴 것으로 한다.At this time, the length of the electric wiring is one embodiment, the length of the electric wiring connecting the backlight 2 (L2) is longer.

여기서, 상기 전류편차보상부(13)는 일 실시예적으로 트랜스포머의 2차측과 접지 사이에 직렬 연결되는 한 쌍의 커패시터1, 2(C1)(C2)와 상기 커패시터 중 접지 측 커패시터2(C2)와 병렬 연결되는 레지스터(R1)를 포함하여 구성된다.Here, the current deviation compensation unit 13 is a pair of capacitors 1, 2 (C1) (C2) and a ground-side capacitor 2 (C2) of the capacitor connected in series between the secondary side of the transformer and the ground in one embodiment And a resistor (R1) connected in parallel with.

이때, 상기 전류편차보상부(13)는 전기배선의 길이가 짧은 경로1(11)에 포함된다.At this time, the current deviation compensation unit 13 is included in the path 1 (11) having a short length of the electrical wiring.

이와 같이 되면, 상기 전류편차보상부(13)가 트랜스포머1(T1)의 2차측에서 출력되는 전원인 전류의 흐름을 변화시킨다. In this case, the current deviation compensator 13 changes the flow of current, which is a power output from the secondary side of transformer 1 (T1).

즉, 트랜스포머1(T1)의 2차측에서 나온 전류가 커넥터1(CON1) 측으로 흐름과 동시에, 전류편차보상부(13)로 일부가 흘러 그라운드 처리되므로, 커넥터1(CON1)을 통해 출력되는 전류가 줄어들게 된다. That is, since the current from the secondary side of the transformer 1 (T1) flows to the connector 1 (CON1) side and partly flows to the current deviation compensator 13 to ground, the current output through the connector 1 (CON1) Will be reduced.

그러므로, 백라이트1(L1) 측으로 인가되는 전류가 백라이트2(L2) 측으로 인가되는 전류보다 작게 출력된다. 그러나, 백라이트2(L2) 측으로 높게 출력된 전류는 전기배선2(W2)를 경유하는 과정에서 즉, 고압 연결에서 일부 전류가 줄어들어 백라이트2(L2)는 백라이트1(L1)과 동일한 전류값을 인가 받아 동일한 휘도를 갖도록 점등된다.Therefore, the current applied to the backlight 1 (L1) side is output smaller than the current applied to the backlight 2 (L2) side. However, the current output high toward the backlight 2 (L2) side is reduced in the process of passing through the electrical wiring 2 (W2), that is, the high voltage connection, so that the backlight 2 (L2) applies the same current value as the backlight 1 (L1). Light up to have the same brightness.

예를 들어, 백라이트1(L1)와 백라이트2(L2)로 각각 100의 전류가 인가되어 동일한 휘도를 가져야 한다고 가정하고, 이때, 백라이트2(L2)로 전류를 제공하는 경로인 전기배선(W2)에서 누설되는 전류가 30이라 할 때, 트랜스포머에서 130이라는 전류를 각각 백라이트1(L1)와 백라이트2(L2)로 공급한다.For example, suppose that 100 currents are respectively applied to the backlight 1 L1 and the backlight 2 L2 to have the same brightness. In this case, the electrical wiring W2, which is a path for providing the current to the backlight 2 L2, is provided. When the leakage current from the device is 30, a current of 130 is supplied from the transformer to the backlight 1 (L1) and the backlight 2 (L2), respectively.

그리하면, 백라이트2(L2)는 상기와 같이, 전기배선2(W2)를 경유하면서 30이라는 전류가 누설되어, 결과적으로 100이라는 전류가 백라이트2(L2)로 인가된다.Then, as described above, the backlight 2 L2 leaks a current of 30 via the electrical wiring 2 W2, and as a result, a current of 100 is applied to the backlight 2 L2.

한편, 백라이트1(L1)에는 전류편차보상부(13)를 구성하는 한 쌍의 커패시터1, 2(C1)(C2)와 상기 커패시터 중 접지 측 커패시터2(C2)와 병렬 연결되는 레지스터(R1)들의 각 시정수(용량)에 의해 130이라는 전류가 100으로 다운(의도적인 다운)되어 제공된다. On the other hand, in the backlight 1 (L1), a pair of capacitors 1, 2 (C1) (C2) constituting the current deviation compensation unit 13 and a resistor (R1) connected in parallel with the ground-side capacitor 2 (C2) of the capacitors. Each time constant (capacitance) of 130 provides a current of 130 down (intentionally down).

결과적으로, 백라이트1(L1)과 백라이트2(L2)에 동일한 전류가 인가되어 백라이트유닛의 휘도 편차가 개선된다.As a result, the same current is applied to the backlight 1 (L1) and the backlight 2 (L2) to improve the luminance deviation of the backlight unit.

이때, 백라이트1(L1)과 백라이트2(L2)의 휘도 편차는 전류편차보상부(13)의 용량값을 조절하여 조정할 수 있다. 그러므로, 상기 전류편차보상부(13)의 커패시터1, 2(C1)(C2)와 레지스터1(R1)은 가변성 소자로 하는 것이 바람직하다. In this case, the luminance deviation between the backlight 1 L1 and the backlight 2 L2 may be adjusted by adjusting the capacitance value of the current deviation compensator 13. Therefore, it is preferable that the capacitors 1, 2 (C1) (C2) and resistor 1 (R1) of the current deviation compensator 13 are variable elements.

이상, 본 발명을 본 발명의 원리를 예시하기 위한 바람직한 실시예와 관련하여 설명하고 도시하였지만, 본 발명은 그와 같이 도시되고 설명된 그대로의 구성 및 작용으로 한정되는 것이 아니다. While the invention has been described and illustrated in connection with a preferred embodiment for illustrating the principles of the invention, the invention is not limited to the configuration and operation as such is shown and described.

오히려, 첨부된 청구범위의 사상 및 범주를 일탈함이 없이 본 발명에 대한 다수의 변경 및 수정이 가능함을 당업자들은 잘 이해할 수 있을 것이다. Rather, those skilled in the art will appreciate that many modifications and variations of the present invention are possible without departing from the spirit and scope of the appended claims.

따라서, 그러한 모든 적절한 변경 및 수정과 균등물들도 본 발명의 범위에 속하는 것으로 간주되어야 할 것이다. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

본 발명에 의하면, PCB가 일측 단에 설치되어 타측 단에 설치되는 백라이트로 전원을 공급하는 경로인 배선의 길이가 길어질 수밖에 없는 One-Board 방식에서 누설전류의 발생이 상대적으로 적은 전원 공급 경로에 의도적인 누설전류를 유도하는 전류편차보상부를 포함시켜, 누설전류가 많은 측의 백라이트와 누설전류가 적은 측의 백라이트로 공급되는 전원의 비율을 동일하게 유지시킬 수 있어, 전원 편차에 의해 발생되는 백라이트유닛의 휘도 편차를 개선시킬 수 있다. According to the present invention, the PCB is intentionally used in a power supply path having a relatively low leakage current in the One-Board method, in which a length of a wiring, which is a path for supplying power to a backlight installed at one end and supplying power to a backlight installed at the other end, is long. Including a current deviation compensator for inducing a leakage current, the ratio of the power supplied to the backlight on the side with a high leakage current and the backlight on the side with a small leakage current can be kept the same, and the backlight unit generated by the power deviation Can improve the luminance deviation.

Claims (5)

적어도 두개의 백라이트; At least two backlights; 상기 백라이트로 각각 전원을 공급하는 전원 공급 경로들; 및 Power supply paths respectively supplying power to the backlight; And 상기 적어도 두개의 전원 공급 경로들중, 경로의 길이가 타경로들 보다 짧은 전원 공급 경로에 연결된 전류편차보상부를 포함하는 액정표시장치의 백라이트유닛 전원공급회로.And a current deviation compensator connected to a power supply path of which the length of the path is shorter than other paths among the at least two power supply paths. 제 1항에 있어서, 상기 각각의 전원 공급 경로는 The method of claim 1, wherein each power supply path is 입력전원을 변압하는 트랜스포머; A transformer for transforming an input power source; 상기 트랜스포머로부터 출력되는 전원을 백라이트와 접속시키는 커넥터가 일측 단에 포함되어, 상기 백라이트와 트랜스포머를 연결하는 전기배선를 포함하는 것을 특징으로 하는 액정표시장치의 백라이트유닛 전원공급회로.And a connector for connecting the power output from the transformer to the backlight at one end thereof, the electrical wiring connecting the backlight and the transformer to the power supply circuit of the liquid crystal display device. 제 2항에 있어서, 상기 전류편차보상부는 The method of claim 2, wherein the current deviation compensation unit 상기 경로의 길이가 타경로들보다 짧은 전원 공급 경로에 포함된 트랜스포머의 2차측과 상기 커넥터사이에 접지측과 병렬 연결되는 것을 특징으로 하는 액정표시장치의 백라이트유닛 전원공급회로.And a ground side connected in parallel with a ground side between a secondary side of a transformer included in a power supply path having a length shorter than other paths and the connector. 제 1항 내지 제 3항 중 어느 한 항에 있어서,The method according to any one of claims 1 to 3, 상기 전류편차보상부는 전원을 누설시키는 소자를 포함하는 것을 특징으로 하는 액정표시장치의 백라이트유닛 전원공급회로.And the current deviation compensating part includes a device for leaking power. 제 4항에 있어서, 상기 전류편차보상부는 The method of claim 4, wherein the current deviation compensation unit 상기 트랜스포머의 2차측과 접지 사이에 직렬 연결되는 한 쌍의 커패시터와 상기 커패시터 중 접지 측 커패시터와 병렬 연결되는 레지스터를 포함하는 것을 특징으로 하는 액정표시장치의 백라이트유닛 전원공급회로.And a pair of capacitors connected in series between the secondary side and the ground of the transformer and a resistor connected in parallel with the ground side capacitor among the capacitors.
KR1020070074054A 2007-07-24 2007-07-24 Power supply circuit of back light unit for liquid crystal display KR20090010718A (en)

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